Applied Microbiology and Biotechnology

, Volume 87, Issue 3, pp 847–857 | Cite as

Pretreatment of woody biomass for biofuel production: energy efficiency, technologies, and recalcitrance

  • J. Y. Zhu
  • Xuejun Pan
  • Ronald S. ZalesnyJr.


This mini review discusses several key technical issues associated with cellulosic ethanol production from woody biomass: energy consumption for woody biomass pretreatment, pretreatment energy efficiency, woody biomass pretreatment technologies, and quantification of woody biomass recalcitrance. Both total sugar yield and pretreatment energy efficiency, defined as the total sugar recovery divided by total energy consumption for pretreatment, should be used to evaluate the performance of a pretreatment process. A post-chemical pretreatment wood size-reduction approach was proposed to significantly reduce energy consumption. The review also emphasizes using a low liquid-to-wood ratio (L/W) to reduce thermal energy consumption for any thermochemical/physical pretreatment in addition to reducing pretreatment temperature.


Recalcitrance Cellulosic ethanol Woody/Forest biomass SPORL Enzymatic hydrolysis/saccharification Pretreatment 



We acknowledge Dr. Carl Houtman of US Forest Service, Forest Products Laboratory, for generously providing us the spreadsheet for thermodynamic calculations of enthalpy of pulp suspensions.


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Copyright information

© US Government 2010

Authors and Affiliations

  • J. Y. Zhu
    • 1
    • 2
  • Xuejun Pan
    • 2
  • Ronald S. ZalesnyJr.
    • 3
  1. 1.USDA Forest ServiceForest Products LaboratoryMadisonUSA
  2. 2.Department of Biological Systems EngineeringUniversity of WisconsinMadisonUSA
  3. 3.USDA Forest ServiceNorthern Research StationRhinelanderUSA

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